母材晶粒取向对超薄取向硅钢织构演化的影响

Effect of grain orientation in raw materials on texture of ultra-thin grain-oriented silicon steel

针对超薄取向硅钢制备过程中不同初始取向晶粒在冷轧及退火过程中取向和显微组织演化规律的差异性,系统研究了母材中主要存在的3类偏离标准Goss取向不同程度的Goss晶粒冷轧和退火行为。结果表明,Ⅰ型-准确Goss取向(偏差角小于3°)晶粒在冷轧过程形成锋锐的{111}<112>织构和丰富的形变带及剪切带,剪切带和形变带内均存在少量Goss取向区域;退火过程中此类区域中Goss取向晶粒优先形核,其中剪切带形核比例较大,最终获得以Goss织构组分为主的(<100>//RD)织构,平均晶粒尺寸相对较小。Ⅱ型-η线型({0kl}<100>,k,l≠1)偏Goss取向(偏差角<10°)晶粒冷轧过程形成{111}<112>和{113}<361>织构,剪切带和形变带内均存在少量η线取向组分,而{113}<361>取向区域无剪切带形成;退火过程中剪切带和形变带内的η线取向晶粒优先形核,而大量不均匀分布的非η线取向形核晶粒存在且长大优势明显,最终获得不均匀的退火组织,且η线取向晶粒占比较低。Ⅲ型-{011}型偏Goss取向(偏差角小于10°)晶粒的形变再结晶行为与Ⅰ型取向晶粒相似,但冷轧过程形成强度相对弱的{111}<112>织构,而再结晶织构呈现沿η线的漫散分布特征;退火过程中η线取向晶粒优先形核同样主要发生在剪切带与形变带内,但是非η取向晶粒形核分布较为均匀且后续长大优势不明显;退火组织中η线取向晶粒占比较高,组织均匀性较好且平均晶粒尺寸相对较大。综合考虑组织织构演变规律,应选择Ⅱ型取向晶粒占比较少、Ⅲ型取向晶粒占比适中的母材制备超薄取向硅钢。

Considering the different microstructure and texture evolution laws for different oriented grains in raw material during cold rolling and annealing processes in the preparation of ultra-thin grain-oriented silicon steel,the deformation and recrystallization behaviors of three types of grains with different deviation from exact Goss orientation was analyzed.It was found that,forⅠ-type(exact Goss)grains,sharp{111}<112>texture and abundant shear bands and deformation bands were formed during cold rolling,and a small amount of Goss oriented areas were observed in shear bands and deformation bands.During annealing,Goss oriented grains in shear bands and deformation bands nucleated preferentially,with the majority existing in shear bands,thenη-fiber texture peaked at Goss component and uniform structure with relative lower average grain size were obtained.ForⅡ-type({0kl}<100>,k,l≠1)oriented grains,{111}<112>and{113}<361>textures were formed during cold rolling.There existed a small amount ofηfiber areas in shear bands and deformation bands,while no shear bands were obtained in{113}<361>oriented regions.During annealing,η-fiber nucleation in shear bands and deformation bands occurred preferentially,and a large number of non-ηfiber oriented nuclei presented an uneven distribution,then showed obvious growth advantage in following stage and thus obtained an uneven annealing structure with a lower proportion ofη-fiber grains.The deformation and recrystallization behaviors ofⅢ-type({011}<uvw>)grains were similar to that ofⅠ-type grains,while a lower intensity of{111}<112>texture was obtained during cold rolling,and the recrystallization texture showed a diffuse distribution characteristic alongη-fiber;During annealing,η-fiber orientated grains also nucleated preferentially mainly in shear bands and deformation bands.The nucleated non-η-fiber grains presented a uniform distribution,and not marked uneven annealed microstructure with a higher proportion ofη-fiber grains and relative larger average grain size were achieved.By overall considering microstructure and texture,the raw material with lower proportion ofⅡ-type grains and moderate proportion ofⅢ-type grains can be used to prepare ultra-thin oriented-grain silicon steel.